Effect of peripheral interference and attentional loss on divided listening to multiple simultaneous talkers

Abstract

Effects of two factors, peripheral interference (masking) and attentional loss, that may impose restriction on divided listening were investigated using Japanese words. In each trial in the divided listening task, simultaneous multiple voices were presented first, then followed by a target voice produced by one speaker. Participants reported whether the target was included in the multiple voices or not. When the number of talkers (manipulated from one to six) was more than three, the estimated hit ratio was lower than unity, and decreased monotonically as the number of talkers increased. To investigate factors inducing the decrement, participants were also tested when the target was presented before the multiple voices. In this condition, decrement of the performance as a function of the number of talkers was gradual, compared to that in the divided listening condition. Decrement of the performance in the pretarget condition was thought to come mainly from peripheral interference, and the difference between the two tested conditions was interpreted as representing the cost in dividing attention. The result suggests that failure in divided listening to three or four talkers largely comes from the attentional factor, although the role of peripheral interference becomes larger when there are more talkers.